Depth charge and like submarine explosive body



Aug.` 23, 1927.

H B PRATT DEPTH CHARGE AND LIKE SUBMARINE EXPLOSIVE BODY Filed` oct,

g H. B. PRATT DEPTH CHARGE ANDLIKE SUBMARINE EXPLOSIVE BODY FiledOct. 1.1925 2 Sheets-Sheet 2 Patented Aug. `23, 1927.

Unirse STATES HARTLEY IBLYTH PRATT, OF BARROW-IN-FURNESS, ENGLAND,ASSIGNOR TO VICK- ERS LIMITED, OF WESTMINSTER,

ENGLAND, A BRITISH COMPANY.

DEPTH CHARGE AND LIKE SUBMARINE EXPLOSIVE BODY.

Application led October 1, 1925, Serial No. 59,808, and in Great BritainOctober 3,1924.

This invention relates to depth charges and like submarine explosivebodies. More particularly the invention relates to socalled depthcharges or like bodies which are adapted to fire automatically onreaching a predetermined depth.

It has been proposed to lire such depth charges at a predetermined depthby means of hydrostatically operated mechanism and one form of suchmechanism involves the use of a timing device comprising a chamber intowhich water can flow at varying selected rates, the arrangement-beingsuch that the time taken to fill the chamber to the required extent foro erating the hydrostat and so firing the dept charge is equal to orsubstantially equal to the time taken for the body to sink freely to aspecified depth,

and the chief object of the present invention is to provide a submarineexplosive body the firing mechanism of which is directly operated by thehydrostatic pressure and independently of the speed or time taken forthe depth charge to sink to the desired depth.

According to the present invention the regulation of the firing depth iseffected by varying the volume into which a quantity of trapped air iscompressed. To this end a quantity of air may be trapped betweenrelatively movable parts, one or both said parts being acted upon by thehydrostatic pressure and the arrangement being such that automaticfiring takes place when the water pressure brings the relatively movableparts into correct relative firing position. The depth at which ring isadapted to take lace may be controlled as desired by vary-- 111g thecapacity of an air space or spaces so as to increase or diminish thevolume of air initially trapped between the aforesaid relatively movableparts.l Consequently the external Water pressure (and hence the depth ofsinking), which is required to re the explosive body willbe that whichis necessary to'compress any particular volume of trapped air to theextent which is necessary to allow the relatively' movable parts toreach the firing position.

4 In the case of a depth charge, the pistol and primer may be locatedwithin la tubular casing, and air may be trapped in said tubular casing`between the piston and the primer. The primer itself may be movableunder the influence of the hydrostatic pressure so that it acts as apiston which will compress the air trapped in the said tubular casing.The primer'is normally located some distance away from the pistol, and,after launching of the depth charge, and under the influence of thehydrostatic pressure the primer will move forward along the tubularcasing and compress the trapped air. When sufficient hydrostaticpressure is available to move the primer into correct relative firingposition with regard to the pistol, the pistol is automatically actuatedand explodes the depth charge. Additional air spaces, suitablycontrolled by a valve or the like may also be provided one or more ofsaid air spaces being adapted to tbe placed in communication with theair space between the pistol and primer units so as to vary the ringdepth.

In order that the said invention may be clearly understood and readilycarried into effect the same will now be described more fully withreference to the accompanying drawing, in which Figure l is alongitudinal section` of a depth charge constructed accordingto one`embodiment of the present invention, the

parts being shown in the position which they occupy prior to launchingof the depth charge.

Figure 2 is a detail view of part of the depth charge showing the primerand pis-V tol in the tiring position.

Figure 8 is a section on the line X-X of Figure 1, and

Figure 4 is a View looking down on the head of the piston and showingthe depth indicating dial. I

Figure 5 is a view corresponding to Flgure 1 showing a modifiedconstruction of depth charge, and Figure 6 is a detail view showing thedepth indicating dial.

Referring to the embodiment of the invention shown at Figures 1 toil, Ais a guide tube located centrally of a main casing or charge case B,which contains the bursting charge C, the guide tube A beingwelded atone end a directly to the charge case B, its other 'end being welded toa flanged part a2 ofthe charge case. The primer D1'1s located within acasing D (hereinafter termed the primer case) whlch is of cy lindricalformation and s lidably mounted within the guide tube A so as toact as apiston or plunger. Normally the primer case F through passages Z,

D is located at one extreme end of the guide tube Al (as shown at Figure1,), and, to hold it in this position up to launching of the depthcharge, the primer case D may be provided with a projecting part d whichextends through a bun or closure plate d1" positioned Within the guldetube A, the said bung or? closure plate Z1-having openings Z2 foradmitting water to the guide tube A. The primer case D is normally heldin the position shown at-Figure 1 by means of a safety pin d3which'engages a recess in the said projecting part al said pin d3 beingremoved before the depth char e is launched. An airtight joint between te primer case D and' the guide tube A may be effected in any desiredmanner, for example, by providing a ring of rubber or other flexiblematerial al* between the primer case D and the guide tube A, said rubberring d4 being adapted to allow the' primer case D to move relatively tothe guide tube A while atthe same time preserving an air and Water-ti htjoint. E is the pistol which is secure by bolts e to the flange aF so asto form an air-tight joint, and is located at the opposite end of theguide tube A. e1 is a detonator which is mounted at the end'of a tube e3(hereinafter termed the detonator carrier)l which projects into theguide tube A. The striker e4 is located within the detonator carrier e3and said striker is provided with a flange e5, between which and a-pluge6 a firing spring e7 is located, The detonator carrier e3 and thestriker e4 are capable of relative sliding movement but `such move-'ment is normally vprevented by means of suitable releasing devices,such for example as a so-called ball release, the laterally displaceableballs e8 being located within a slot in the detonator carrier e3 andprojecting into a groove in the striker e4. Surrounding the striker e4and the detonator carrier e8 is a casing e9 (hereinafter termed thestriker casing), the detonator carrier e3 being provided with a flangeat its inner end which flange is normally held against a shoulder 01 onthe striker casing e by the striker spring e7.' Positioned around thestriker casing e9 in a hollow box-like part F (hereinafter termed theairy chamber) which is divided into compartments f1, f1 of differentsizes by means of division plates f, f.' Air spaces are thereforeprovided and one or more of said spaces can be placed as desired incommunication with the main air space Gr in the guide tube A by'suitablemeans. For example a rotatable plate valve H may be provided which isformed with openings k which can be manipulated as desired to place one'or more of the compartments f1, f1 in' the air chamber in communication,with the air space G in the guide tube The plate valve HA is positionedaround the striker casing e"v f3 of the air chamber F by means of aspring I located between the plate valve H and a nut z' on the strikercasing e9. The part of the striker casing e9 which projects beyond thebase of the depth charge may be provided with a pointer @1 and, on thecontiguous part of the air chamber a scale or a series of calibrationsf4 (Figure 4) may be provided so as to indicate the adjusted depth atwhich firing will take place. For example, when the air chamber F is notin use the air trapped in the space G between the primer case D and theplate valve H may be adapted to fire the pistol at a depth of 300 feet.Where for example and as shown at Figure 3 four* compartments areprovided in the air chamber P the arrangement may be such that when oneof said compartments f1 is added to the clearance volume G in the guidetube A the depth charge will fire at 200 feet; lwhen another compartmentis added the depth chargeV will fire at 150 feet; when a thirdcompartment is added the depth charge will fire at feet and when thefourth compartment is added the depth chargewill fire at 50 feet.Regulation of the volume of trapped air, or in other words the number ofcompartments added to the clearance volume in the guide tube A, I

is effected by rotatino the plate valve H by` means of a key applied tothe part e on the end of the striker casing e. The striker casing e" isprovided with splines e11 which engage the plate valve H -so as to causethe latter to turn'with the striker casing e9; When the pointer elo onthe striker casing e9 is brought opposite a calibration corresponding toa particular depth the required openings z, in the plate valve H willregister with the requisite passage or passages f2, f2 communicatingwith an appropriate compartment f1 or compartments f1, f1 in the airchamber F. The rotaton'of the striker casing e9 and consequently theplate valve H may be controlled by means of a detent e12 provided either`at the base of the air chamber or (as shown) on the pointer el carriedby the striker casing e9 the detent e12 being hld within a seat eitheron the air chamber or on the pointer by the pressure exerted by thespring I located between the plate valve H and the flange lon thestriker casing.` By a forcible effort exerted by means of the aforesaidkey the detent e12 is-lifted out of its seat and the striker casingegfis turned and the detent will thereafter' slip into the next seatcorresponding to any particular calibration.

The primer case D, as aforesaid, is normally held at the top of thedepth charge by means of a safety pin d3. When this safety pin isremoved and the depth charge launched, Water passes through the openingsdz in the bung or cover plate d* and zoo i fire after the tiringpressure.

the hydrostatic pressure acts on the outer end of the primer case D andalso on the aforesaid rolling rubber ring d2. The primer case D istherefore pushed up the guide tube A and compresses the air between theinner end of the saine and the plate valve H or the air compartments inthe air chambers F if any of' them have been opened. Leakage of airoutwards or water inwards is etfectually prevented by the rolling rubberring d4 and accordingly the external water pressure and the internal airpressure will be substantially the same, the water pressure beingslightly greater so as to overcome the sliding friction of the rollingrubber ring (Z4. There is therefore no tendency for air to leak outwardsand with the slight difference in pressure on each side of the rubberring Z" the latter effeetually prevents water leakage inwards. Thepistol E as aforesaid, is adapted to hydrostatic pressure has pushed theprimer case D up to the top of the guide tube A into a position wherethe detonator e1 projects into a recessed part Z1 in the primer case D.When the parts are in this position the detonator carrier e3 is pushedalong the striker cA1 and compresses the striker spring e1 thecompressing action being continued until the balls e13 of the ball'release pass beyond the 'shoulder in the striker casing whereupon theymove laterally outwards and disconnect the striker from the detonatorcarrier. The reaction of the striker spring then forces the strikerviolently in contact with the detonator exploding the same anddetonating the primer, and consequently exploding the main burstingcharge.

In the modified arrangement shown at Figure 5 the same reference lettershave been employed to designate the same or corresponding parts of thedepth charge. In this embodiment of the invention, however, two airchambers K1 and K2 only are rovided in the pistol. adapted to be placedinto communication with the space G by a port le and the chamber K1 isadapted-to be placed into communication with the space G by means of atube k1 extending through the chamber K2, the port k and the tube k1being controlled as before by a rotatable plate valve H having ports h,l1. formed therein. The capacity of these three air chambers G, K1 andK2 may be such as to provide for three depth settings. namely 60, 120and 180 feet. For the 1.80 feet setting bot-h the chambers K1 and K2 areclosed of so that the clearance volume G in the guide tube A determinesthe For the 120 feet the volume K2 is added and for 60 feet the volumesK1 and K2 are added.

If desired additional air chambers can also be provided if more depthsettings are The chamber I 2 isr required. The adjusting mechanism forrotating the plate valve H comprises a nut H1 secured to the striker c4the plate valve H being integral with or rigidly connected to the lowerend of the striker e1 so that it rotates therewith. Splines I", F areprovided between the rotatable nut and the casing Within which thestriker is adapted to rotate. The nut H preferably carries a pointer H2which serves the combined function of rotating the nut H and at the sametime indicating the particular calibration on the dial H2 to which thepointer has been adjusted.

To renderthe pistol safe when the pointer is set to the calibration Safethe part L is provided with a serrated flange L1 and correspondingseirations M1, M1 are cut in the. body portion M. When the setting atSafe the serrations L1 are located opposite the serrations M1 thuspreventing movement of the part L and consequently preventing .operationof the pistol release. lVlien, however, the pointer H2 is moved over toindicate a depth setting the serra-- tions L1 allow the part L to movethrough the part M1.

Instead of providing av fixed pistol unit and a moving primer unit theprimer can be fixed and the pistol unit can be adapted to move, or,alternatively both the pistol and primer units may be adapted to moveinwards simultaneously so as to effect the eX- plosion of the mine vinthe manner previously described. f

Vhat I claim and desire to secure by Letters Patent of the United Statesis 1. A depth charge or like submarine body comprising members movablerelatively to one another under the influence of the hydrostaticpressure, means for automatically exploding the body when said memberscome into contact with one another and means for varying the volume ofair compressed by said members in moving into contact with one anotherso as to vary the depth at which automatic firing takes place.

2. A depth charge or like submarine explosive body comprising memberswhich are normally situated apart and between which a predeterminedvolume of air is trapped, said members being adapted to move towards oneanother under the influence of the hydrostatic pressure, means fortrapping a predetermined volume of' air between said relatively movablemembers and means for automatically firin the body when the hydrostaticpressure as compressed the predetermined volume of trapped air to theextent which is'necessary vto bring said relatively movable members intocorrect relative tiring position.

3. A depth charge in which the automatic tiring gear comprises aplurality o f units which are movable into contact with one anotherunder the iniuence of the hydrostatic pressure and means for varying thevolume of air which is compressed by said units in moving into contactwith one another so as to vary the depth at Which automatic firing takesplace.

4. A depth charge or like submarine explosive body comprising two unitswhich are movable towards one another under the influence of thehydrostatic pressure, means for trapping a predetermined volume of airbetween said relatively movable units and means for automatically ringthe body when the hydrostatic pressure has com-v pressed thepredetermined volume of trapped air to the extent which is necessary tobring the said relatively movable parts into corvrect relative ringposition.

5. A depth charge or like submarine explosive body comprising a tubularcasing, a pistol and a primer unit located within said tubular casing,said pistol and primer units vbeing separated by an air space, means fortrapping apredetermined volume of air in said air space, said primerunit being movable under the influence' of the hydrostatic pressure soas to compress the air trapped 1n said air space for the purposespecified.

plosive. body comprising a Atubular casing,

a pistol and a primer unit located within said tubular casing, saidpistol and primer units being separated by an air space, means fortrapping a predetermined volume of air in said air space, said pistolunit being movable under the influence of the hydrostatic pressure so asto compress the airv said air space for the purpose being separated byan air space withinA which a predetermined volume of air is trapped,both said` units 'being movable under the influence of the hydrostaticpressure -so as to compress the air trapped-in said air space for thepurpose specified.

8. A depth charge or like submarine explosive body comprising a tubularcasing, pistol and primer units located Within said tubular casing, withan air space between said pistol and primer units, and means for placingadditional air spacesin communication with the air space between saidpistol and primer units for 'the purpose specified,

HARTLEY BLYTI-I` PRATT.

